Virgin Atlantic is under mounting pressure to answer allegations that a senior employee passed private flight details for almost 70 celebrities – including Princess Beatrice and Madonna's children – to a global paparazzi agency.

Further emails seen by the Guardian on Friday suggest that London-based firm Big Pictures was sent confidential travel details for dozens of celebrities and public figures as recently as 2011.

Virgin Atlantic and Big Pictures launched internal investigations into the claims on Thursday. A spokeswoman for Virgin Atlantic declined to comment on the further revelations, but said they would form part of the airline's inquiry.

Checks by the Guardian confirm that at least some of the 68 celebrities – such as Jeremy Clarkson, James May and the wife of footballer Wayne Rooney – were in the travel destinations apparently disclosed by the Virgin Atlantic employee.

The further emails indicate that the disclosure of private flight details to the paparazzi is on a much larger scale than initially thought.

Those named in the emails include Princess Beatrice, Russell Brand, Rihanna, Daniel Radcliffe and Madonna's children.

Big Pictures appears to have been given a secret tip-off by the Virgin Atlantic employee that people only referred to as "Madonna's kids" would be flying to JFK airport from Heathrow with the airline in September last year.

Another email lists the travel plans for ex-England football manager Glen Hoddle with Virgin Atlantic to Barbados in November last year. The email says: "There's loads of ex-footballers on these flights going out for a charity golf classic."

A separate email apparently from the airline employee details a flight for the comedian Sacha Baron Cohen and his wife Isla Fisher from Heathrow to Newark airport last year and says: "They're in economy!!!!!".

In a statement, Virgin Atlantic said on Thursday that it was taking the apparent leak "extremely seriously". The company said: "The allegations that have been raised are extremely serious and we have launched an immediate investigation.

"The security of customer information is our highest priority and we have robust processes in place to ensure that passenger information is protected. The incident that has been alleged concerns eight customers' flights booked in 2010 and we are in contact with all of those people. It is too early to draw conclusions on this matter but of course we would deeply regret any concern that these allegations may cause the individuals involved."

Big Pictures had not returned repeated requests for comment at the time of publication.

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